2-(substituted phenyl)-6-hydroxy or alkoxy-5-substituted-4-pyrimidinecarboxylates and their use as herbicides

ABSTRACT

2-(Substituted phenyl)-6-hydroxy or alkoxy-5-substituted-4-pyrimidinecarboxylic acids and their derivatives are herbicides demonstrating a broad spectrum of weed control.

BACKGROUND OF THE INVENTION

This application claims the benefit of U.S. Provisional Application Ser. No. 61/124,695 filed on Apr. 18, 2008. This invention relates to 2-(substituted phenyl)-6-hydroxy or alkoxy-5-substituted-4-pyrimidinecarboxylic acids and their derivatives and to the use of these compounds as herbicides.

A number of pyrimidinecarboxylic acids and their pesticidal properties have been described in the art. U.S. 2007/0197391 A1 and U.S. Pat. No. 7,300,907 B2 generically disclose 2-substituted-6-amino-4-pyrimidinecarboxylic acids and their derivatives and their use as herbicides. U.S. 2009/0043098 describes certain 2-substituted-1,6-dihydro-6-oxo-4-pyrimidinecarboxylic acids and their use in preparing 2-substituted-6-amino-4-pyrimidinecarboxylic acids.

SUMMARY OF THE INVENTION

It has now been found that 2-(substituted phenyl)-6-hydroxy or alkoxy-5-substituted-4-pyrimidinecarboxylic acids and their derivatives are herbicides with a broad spectrum of weed control against broadleaf weeds as well as grass and sedge weeds and with excellent crop selectivity at low use rates. The compounds further possess excellent toxicological or environmental profiles.

The invention includes compounds of Formula I:

wherein

Q represents a halogen, cyano, C₁-C₄ alkyl, C₁-C₄ haloalkyl, C₂-C₄ alkenyl and epoxides thereof, C₂-C₄ haloalkenyl and epoxides thereof, C₂-C₄ alkynyl, C₂-C₄ haloalkynyl, C₁-C₄ alkoxy, C₁-C₄ haloalkoxy, C₁-C₄ alkylthio or C₁-C₄ haloalkylthio;

R₁ represents H or C₁-C₄ alkyl;

W represents H or halogen;

X represents H or halogen;

Y represents halogen, C₁-C₄ alkyl, C₁-C₄ alkoxy, C₁-C₄ alkylthio, C₁-C₄ haloalkyl, C₁-C₄ haloalkoxy, C₁-C₄ haloalkylthio, —NR₂R₃, C₁-C₄ alkoxy-substituted C₁-C₄ alkyl, C₁-C₄ haloalkoxy-substituted C₁-C₄ alkyl, C₂-C₄ alkenyl, C₂-C₄ haloalkenyl or C₁-C₄ haloalkyl-substituted carbonyl;

Z represents halogen, C₁-C₄ alkyl or C₁-C₄ haloalkyl; and

R₂ and R₃ independently represent H or C₁-C₄ alkyl; and agriculturally acceptable derivatives of the carboxylic acid group.

Preferred compounds of formula (I) independently include those in which Q represents Cl, Br, C₂-C₄ alkenyl or C₁-C₄ alkoxy; R₁ represents H; W represents H; X represents H or F; Y represents F or OCH₃; and Z represents Cl.

The invention includes herbicidal compositions comprising an herbicidally effective amount of a compound of Formula I and agriculturally acceptable derivatives of the carboxylic acid group in admixture with an agriculturally acceptable adjuvant or carrier. The invention also includes a method of use of the compounds and compositions of the present invention to kill or control undesirable vegetation by application of an herbicidal amount of the compound to the vegetation or to the locus of the vegetation as well as to the soil prior to emergence of the vegetation.

DETAILED DESCRIPTION OF THE INVENTION

The herbicidal compounds of the present invention are derivatives of 2-(substituted phenyl)-6-hydroxy-5-substituted-4-pyrimidinecarboxylic acid:

wherein

Q represents a halogen, cyano, C₁-C₄ alkyl, C₁-C₄ haloalkyl, C₂-C₄ alkenyl and epoxides thereof, C₂-C₄ haloalkenyl and epoxides thereof, C₂-C₄ alkynyl, C₂-C₄ haloalkynyl, C₁-C₄ alkoxy, C₁-C₄ haloalkoxy, C₁-C₄ alkylthio or C₁-C₄ haloalkylthio;

W represents H or halogen;

X represents H or halogen;

Y represents halogen, C₁-C₄ alkyl, C₁-C₄ alkoxy, C₁-C₄ alkylthio, C₁-C₄ haloalkyl, C₁-C₄ haloalkoxy, C₁-C₄ haloalkylthio, —NR₂R₃, C₁-C₄ alkoxy-substituted C₁-C₄ alkyl, C₁-C₄ haloalkoxy-substituted C₁-C₄ alkyl, C₂-C₄ alkenyl, C₂-C₄ haloalkenyl or C₁-C₄ haloalkyl-substituted carbonyl;

Z represents halogen, C₁-C₄ alkyl or C₁-C₄ haloalkyl; and

R₂ and R₃ independently represent H or C₁-C₄ alkyl.

The hydroxy group at the 6-position of the pyrimidine ring can be unsubstituted or substituted with a C₁-C₄ alkyl substituent. The hydroxy group can be further derivatized as an ester, a carbamate, a carbonate, a sulfonic ester or a phosphate ester. Such derivatives are capable of breaking down into the hydroxy group.

The carboxylic acids of Formula I are believed to be the compounds that actually kill or control undesirable vegetation and are typically preferred. Analogs of these compounds in which the acid group of the pyrimidine carboxylic acid is derivatized to form a related substituent that can be transformed within plants or the environment to an acid group possess essentially the same herbicidal effect and are within the scope of the invention. Therefore, an “agriculturally acceptable derivative”, when used to describe the carboxylic acid functionality at the 4-position, is defined as any salt, ester, acylhydrazide, imidate, thioimidate, amidine, amide, orthoester, acylcyanide, acyl halide, thioester, thionoester, dithiolester, nitrile or any other acid derivative well known in the art which (a) does not substantially affect the herbicidal activity of the active ingredient, i.e., the 2-(substituted phenyl)-6-hydroxy or alkoxy-5-substituted-4-pyrimidinecarboxylic acid, and (b) is or can be hydrolyzed, oxidized or metabolized in plants or soil to the 2-(substituted phenyl)-6-hydroxy or alkoxy-5-substituted-4-pyrimidinecarboxylic acid that, depending upon the pH, is in the dissociated or the undissociated form. The preferred agriculturally acceptable derivatives of the carboxylic acid are agriculturally acceptable salts, esters and amides.

Suitable salts include those derived from alkali or alkaline earth metals and those derived from ammonia and amines. Preferred cations include sodium, potassium, magnesium, and aminium cations of the formula: R₄R₅R₆NH⁺ wherein R₄, R₅ and R₆ each, independently represents hydrogen or C₁-C₁₂ alkyl, C₃-C₁₂ alkenyl or C₃-C₁₂ alkynyl, each of which is optionally substituted by one or more hydroxy, C₁-C₄ alkoxy, C₁-C₄ alkylthio or phenyl groups, provided that R₄, R₅ and R₆ are sterically compatible. Additionally, any two of R₄, R₅ and R₆ together may represent an aliphatic difunctional moiety containing 1 to 12 carbon atoms and up to two oxygen or sulfur atoms. Salts of the compounds of Formula I can be prepared by treatment of compounds of Formula I with a metal hydroxide, such as sodium hydroxide, or an amine, such as ammonia, trimethylamine, diethanolamine, 2-methylthiopropylamine, bisallylamine, 2-butoxyethylamine, morpholine, cyclododecylamine, or benzylamine. Amine salts are often preferred forms of the compounds of Formula I because they are water-soluble and lend themselves to the preparation of desirable aqueous based herbicidal compositions.

Suitable esters include those derived from C₁-C₁₂ alkyl, C₃-C₁₂ alkenyl or C₃-C₁₂ alkynyl alcohols, such as methanol, iso-propanol, butanol, 2-ethylhexanol, butoxyethanol, methoxypropanol, allyl alcohol, propargyl alcohol or cyclohexanol. Esters can be prepared by coupling of the 2-(substituted phenyl)-6-hydroxy or alkoxy-5-substituted-4-pyrimidinecarboxylic acid with the alcohol using any number of suitable activating agents such as those used for peptide couplings such as dicyclohexylcarbodiimide (DCC) or carbonyl diimidazole (CDI), by reacting the corresponding acid chloride of 2-(substituted phenyl)-6-hydroxy or alkoxy-5-substituted-4-pyrimidinecarboxylic acid with an appropriate alcohol, by reacting the 2-(substituted phenyl)-6-hydroxy or alkoxy-5-substituted-4-pyrimidinecarboxylic acid with an appropriate alcohol in the presence of an acid catalyst or by transesterification. Suitable amides include those derived from ammonia or from C₁-C₁₂ alkyl, C₃-C₁₂ alkenyl or C₃-C₁₂ alkynyl mono- or di-substituted amines, such as but not limited to dimethylamine, diethanolamine, 2-methylthiopropylamine, bisallylamine, 2-butoxyethylamine, cyclododecyl-amine, benzylamine or cyclic or aromatic amines with or without additional heteroatoms such as but not limited to aziridine, azetidine, pyrrolidine, pyrrole, imidazole, tetrazole or morpholine. Amides can be prepared by reacting the 2-(substituted phenyl)-6-hydroxy or alkoxy-5-substituted-4-pyrimidinecarboxylic acid chloride, mixed anhydride, or carboxylic ester of Formula I with ammonia or an appropriate amine.

The terms “alkyl”, “alkenyl” and “alkynyl”, as well as derivative terms such as “alkoxy”, “acyl”, “alkylthio” and “alkylsulfonyl”, as used herein, include within their scope straight chain, branched chain and cyclic moieties. The terms “alkenyl” and “alkynyl” are intended to include one or more unsaturated bonds.

Unless specifically limited otherwise, the term “halogen” including derivative terms such as “halo” refers to fluorine, chlorine, bromine, and iodine.

The compounds of Formula I can be made using well-known chemical procedures. Many procedural details for making compounds of Formula I can be found in the following patent and patent publication: U.S. Pat. No. 7,300,907 B2 and U.S. 2009/0043098. Intermediates not specifically mentioned in the above patent applications are either commercially available, can be made by routes disclosed in the chemical literature, or can be readily synthesized from commercial starting materials utilizing standard procedures.

As shown in Scheme 1, the 2-(substituted phenyl)-6-hydroxy-5-substituted-4-pyrimidinecarboxylic acid esters of Formula I can be prepared by nitrous acid mediated hydrolysis of the 6-amino compound of Formula II.

The method of Scheme 1 is illustrated in Examples 1 and 4.

Alternately, as shown in Scheme 2 compounds of Formula I may be prepared from compounds of Formula III by halogenation with typical reagents, such as the bromine, chlorine or N-halosuccinimides. The method of Scheme 2 is illustrated in Example 3.

It is recognized that some reagents and reaction conditions disclosed herein or in the chemical literature for preparing compounds of Formula I may not be compatible with certain functionalities present in the intermediates. In these instances, the incorporation of protection/deprotection sequences or functional group interconversions into the synthesis will aid in obtaining the desired products. The use and choice of the protection groups will be apparent to one skilled in chemical synthesis.

One skilled in the art will recognize that, in some cases, after the introduction of a given reagent as disclosed herein or in the chemical literature, it may be necessary to perform additional routine synthetic steps not described in detail to complete the synthesis of compounds of Formula I. One skilled in the art will also recognize that it may be necessary to perform a combination of the steps disclosed herein or in the chemical literature in an order other than that implied by the particular sequence presented to prepare the compounds of Formula I.

Finally, one skilled in the art will also recognize that compounds of Formula I and the intermediates described herein or in the chemical literature can be subjected to various electrophilic, nucleophilic, radical, organometallic, oxidation, and reduction reactions to add substituents or modify existing substituents.

The compounds of Formula I have been found to be useful as pre-emergence and post-emergence herbicides. They can be employed at non-selective (higher) rates of application to control a broad spectrum of the vegetation in an area or at lower rates of application for the selective control of undesirable vegetation. Areas of application include pasture and rangelands, roadsides and rights of way, power lines and any industrial areas where control of undesirable vegetation is desirable. Another use is the control of unwanted vegetation in crops such as corn, rice and cereals. They can also be used to control undesirable vegetation in tree crops such as citrus, apple, rubber, oil palm, forestry and others. It is usually preferred to employ the compounds postemergence. It is further usually preferred to use the compounds to control a wide spectrum of woody plants, broadleaf and grass weeds, and sedges. Use of the compounds to control undesirable vegetation in established crops is especially indicated. While each of the 2-(substituted phenyl)-6-hydroxy or alkoxy-5-substituted-4-pyrimidine-carboxylate compounds encompassed by Formula I is within the scope of the invention, the degree of herbicidal activity, the crop selectivity, and the spectrum of weed control obtained varies depending upon the substituents present. An appropriate compound for any specific herbicidal utility can be identified by using the information presented herein and routine testing.

The term herbicide is used herein to mean an active ingredient that kills, controls or otherwise adversely modifies the growth of plants. An herbicidally effective or vegetation controlling amount is an amount of active ingredient which causes an adversely modifying effect and includes deviations from natural development, killing, regulation, desiccation, retardation, and the like. The terms plants and vegetation include germinant seeds, emerging seedlings and established vegetation.

Herbicidal activity is exhibited by the compounds of the present invention when they are applied directly to the plant or to the locus of the plant at any stage of growth or before planting or emergence. The effect observed depends upon the plant species to be controlled, the stage of growth of the plant, the application parameters of dilution and spray drop size, the particle size of solid components, the environmental conditions at the time of use, the specific compound employed, the specific adjuvants and carriers employed, the soil type, and the like, as well as the amount of chemical applied. These and other factors can be adjusted as is known in the art to promote non-selective or selective herbicidal action. Generally, it is preferred to apply the compounds of Formula I postemergence to relatively immature undesirable vegetation to achieve the maximum control of weeds.

Application rates of about 10 to about 1,000 g/Ha are generally employed in postemergence operations; for preemergence applications, rates of about 20 to about 2,000 g/Ha are generally employed. The higher rates designated generally give non-selective control of a broad variety of undesirable vegetation. The lower rates typically give selective control and can be employed in the locus of crops.

The herbicidal compounds of the present invention are often applied in conjunction with one or more other herbicides to control a wider variety of undesirable vegetation. When used in conjunction with other herbicides, the presently claimed compounds can be formulated with the other herbicide or herbicides, tank mixed with the other herbicide or herbicides or applied sequentially with the other herbicide or herbicides. Some of the herbicides that can be employed in conjunction with the compounds of the present invention include: amide herbicides such as allidochlor, beflubutamid, benzadox, benzipram, bromobutide, cafenstrole, CDEA, chlorthiamid, cyprazole, dimethenamid, dimethenamid-P, diphenamid, epronaz, etnipromid, fentrazamide, flupoxam, fomesafen, halosafen, isocarbamid, isoxaben, napropamide, naptalam, pethoxamid, propyzamide, quinonamid and tebutam; anilide herbicides such as chloranocryl, cisanilide, clomeprop, cypromid, diflufenican, etobenzanid, fenasulam, flufenacet, flufenican, mefenacet, mefluidide, metamifop, monalide, naproanilide, pentanochlor, picolinafen and propanil; arylalanine herbicides such as benzoylprop, flamprop and flamprop-M; chloroacetanilide herbicides such as acetochlor, alachlor, butachlor, butenachlor, delachlor, diethatyl, dimethachlor, metazachlor, metolachlor, S-metolachlor, pretilachlor, propachlor, propisochlor, prynachlor, terbuchlor, thenylchlor and xylachlor; sulfonanilide herbicides such as benzofluor, perfluidone, pyrimisulfan and profluazol; sulfonamide herbicides such as asulam, carbasulam, fenasulam and oryzalin; antibiotic herbicides such as bilanafos; benzoic acid herbicides such as chloramben, dicamba, 2,3,6-TBA and tricamba; pyrimidinyloxybenzoic acid herbicides such as bispyribac and pyriminobac; pyrimidinylthiobenzoic acid herbicides such as pyrithiobac; phthalic acid herbicides such as chlorthal; picolinic acid herbicides such as aminopyralid, clopyralid and picloram; quinolinecarboxylic acid herbicides such as quinclorac and quinmerac; arsenical herbicides such as cacodylic acid, CMA, DSMA, hexaflurate, MAA, MAMA, MSMA, potassium arsenite and sodium arsenite; benzoylcyclohexanedione herbicides such as mesotrione, sulcotrione, tefuryltrione and tembotrione; benzofuranyl alkylsulfonate herbicides such as benfuresate and ethofumesate; carbamate herbicides such as asulam, carboxazole chlorprocarb, dichlormate, fenasulam, karbutilate and terbucarb; carbanilate herbicides such as barban, BCPC, carbasulam, carbetamide, CEPC, chlorbufam, chlorpropham, CPPC, desmedipham, phenisopham, phenmedipham, phenmedipham-ethyl, propham and swep; cyclohexene oxime herbicides such as alloxydim, butroxydim, clethodim, cloproxydim, cycloxydim, profoxydim, sethoxydim, tepraloxydim and tralkoxydim; cyclopropylisoxazole herbicides such as isoxachlortole and isoxaflutole; dicarboximide herbicides such as benzfendizone, cinidon-ethyl, flumezin, flumiclorac, flumioxazin and flumipropyn; dinitroaniline herbicides such as benfluralin, butralin, dinitramine, ethalfluralin, fluchloralin, isopropalin, methalpropalin, nitralin, oryzalin, pendimethalin, prodiamine, profluralin and trifluralin; dinitrophenol herbicides such as dinofenate, dinoprop, dinosam, dinoseb, dinoterb, DNOC, etinofen and medinoterb; diphenyl ether herbicides such as ethoxyfen; nitrophenyl ether herbicides such as acifluorfen, aclonifen, bifenox, chlomethoxyfen, chlomitrofen, etnipromid, fluorodifen, fluoroglycofen, fluoronitrofen, fomesafen, furyloxyfen, halosafen, lactofen, nitrofen, nitrofluorfen and oxyfluorfen; dithiocarbamate herbicides such as dazomet and metam; halogenated aliphatic herbicides such as alorac, chloropon, dalapon, flupropanate, hexachloroacetone, iodomethane, methyl bromide, monochloroacetic acid, SMA and TCA; imidazolinone herbicides such as imazamethabenz, imazamox, imazapic, imazapyr, imazaquin and imazethapyr; inorganic herbicides such as ammonium sulfamate, borax, calcium chlorate, copper sulfate, ferrous sulfate, potassium azide, potassium cyanate, sodium azide, sodium chlorate and sulfuric acid; nitrile herbicides such as bromobonil, bromoxynil, chloroxynil, dichlobenil, iodobonil, ioxynil and pyraclonil; organophosphorus herbicides such as amiprofos-methyl, anilofos, bensulide, bilanafos, butamifos, 2,4-DEP, DMPA, EBEP, fosamine, glufosinate, glyphosate and piperophos; phenoxy herbicides such as bromofenoxim, clomeprop, 2,4-DEB, 2,4-DEP, difenopenten, disul, erbon, etnipromid, fenteracol and trifopsime; phenoxyacetic herbicides such as 4-CPA, 2,4-D, 3,4-DA, MCPA, MCPA-thioethyl and 2,4,5-T; phenoxybutyric herbicides such as 4-CPB, 2,4-DB, 3,4-DB, MCPB and 2,4,5-TB; phenoxypropionic herbicides such as cloprop, 4-CPP, dichlorprop, dichlorprop-P, 3,4-DP, fenoprop, mecoprop and mecoprop-P; aryloxyphenoxypropionic herbicides such as chlorazifop, clodinafop, clofop, cyhalofop, diclofop, fenoxaprop, fenoxaprop-P, fenthiaprop, fluazifop, fluazifop-P, haloxyfop, haloxyfop-P, isoxapyrifop, metamifop, propaquizafop, quizalofop, quizalofop-P and trifop; phenylenediamine herbicides such as dinitramine and prodiamine; pyrazolyl herbicides such as benzofenap, pyrazolynate, pyrasulfotole, pyrazoxyfen, pyroxasulfone and topramezone; pyrazolylphenyl herbicides such as fluazolate and pyraflufen; pyridazine herbicides such as credazine, pyridafol and pyridate; pyridazinone herbicides such as brompyrazon, chloridazon, dimidazon, flufenpyr, metflurazon, norflurazon, oxapyrazon and pydanon; pyridine herbicides such as aminopyralid, cliodinate, clopyralid, dithiopyr, fluroxypyr, haloxydine, picloram, picolinafen, pyriclor, thiazopyr and triclopyr; pyrimidinediamine herbicides such as iprymidam and tioclorim; quaternary ammonium herbicides such as cyperquat, diethamquat, difenzoquat, diquat, morfamquat and paraquat; thiocarbamate herbicides such as butylate, cycloate, di-allate, EPTC, esprocarb, ethiolate, isopolinate, methiobencarb, molinate, orbencarb, pebulate, prosulfocarb, pyributicarb, sulfallate, thiobencarb, tiocarbazil, tri-allate and vernolate; thiocarbonate herbicides such as dimexano, EXD and proxan; thiourea herbicides such as methiuron; triazine herbicides such as dipropetryn, triaziflam and trihydroxytriazine; chlorotriazine herbicides such as atrazine, chlorazine, cyanazine, cyprazine, eglinazine, ipazine, mesoprazine, procyazine, proglinazine, propazine, sebuthylazine, simazine, terbuthylazine and trietazine; methoxytriazine herbicides such as atraton, methometon, prometon, secbumeton, simeton and terbumeton; methylthiotriazine herbicides such as ametryn, aziprotryne, cyanatryn, desmetryn, dimethametryn, methoprotryne, prometryn, simetryn and terbutryn; triazinone herbicides such as ametridione, amibuzin, hexazinone, isomethiozin, metamitron and metribuzin; triazole herbicides such as amitrole, cafenstrole, epronaz and flupoxam; triazolone herbicides such as amicarbazone, bencarbazone, carfentrazone, flucarbazone, propoxycarbazone, sulfentrazone and thiencarbazone-methyl; triazolopyrimidine herbicides such as cloransulam, diclosulam, florasulam, flumetsulam, metosulam, penoxsulam and pyroxsulam; uracil herbicides such as butafenacil, bromacil, flupropacil, isocil, lenacil and terbacil; 3-phenyluracils; urea herbicides such as benzthiazuron, cumyluron, cycluron, dichloralurea, diflufenzopyr, isonoruron, isouron, methabenzthiazuron, monisouron and noruron; phenylurea herbicides such as anisuron, buturon, chlorbromuron, chloreturon, chlorotoluron, chloroxuron, daimuron, difenoxuron, dimefuron, diuron, fenuron, fluometuron, fluothiuron, isoproturon, linuron, methiuron, methyldymron, metobenzuron, metobromuron, metoxuron, monolinuron, monuron, neburon, parafluron, phenobenzuron, siduron, tetrafluron and thidiazuron; pyrimidinylsulfonylurea herbicides such as amidosulfuron, azimsulfuron, bensulfuron, chlorimuron, cyclosulfamuron, ethoxysulfuron, flazasulfuron, flucetosulfuron, flupyrsulfuron, foramsulfuron, halosulfuron, imazosulfuron, mesosulfuron, nicosulfuron, orthosulfamuron, oxasulfuron, primisulfuron, pyrazosulfuron, rimsulfuron, sulfometuron, sulfosulfuron and trifloxysulfuron; triazinylsulfonylurea herbicides such as chlorsulfuron, cinosulfuron, ethametsulfuron, iodosulfuron, metsulfuron, prosulfuron, thifensulfuron, triasulfuron, tribenuron, triflusulfuron and tritosulfuron; thiadiazolylurea herbicides such as buthiuron, ethidimuron, tebuthiuron, thiazafluron and thidiazuron; and unclassified herbicides such as acrolein, allyl alcohol, azafenidin, benazolin, bentazone, benzobicyclon, buthidazole, calcium cyanamide, cambendichlor, chlorfenac, chlorfenprop, chlorflurazole, chlorflurenol, cinmethylin, clomazone, CPMF, cresol, ortho-dichlorobenzene, dimepiperate, endothal, fluoromidine, fluridone, flurochloridone, flurtamone, fluthiacet, indanofan, methazole, methyl isothiocyanate, nipyraclofen, OCH, oxadiargyl, oxadiazon, oxaziclomefone, pentachlorophenol, pentoxazone, phenylmercury acetate, pinoxaden, prosulfalin, pyribenzoxim, pyriftalid, quinoclamine, rhodethanil, sulglycapin, thidiazimin, tridiphane, trimeturon, tripropindan and tritac. The herbicidal compounds of the present invention can, further, be used in conjunction with glyphosate, glufosinate, dicamba or 2,4-D on glyphosate-tolerant, glufosinate-tolerant, dicamba-tolerant or 2,4-D-tolerant crops. It is generally preferred to use the compounds of the invention in combination with herbicides that are selective for the crop being treated and which complement the spectrum of weeds controlled by these compounds at the application rate employed. It is further generally preferred to apply the compounds of the invention and other complementary herbicides at the same time, either as a combination formulation or as a tank mix.

The compounds of the present invention can generally be employed in combination with known herbicide safeners, such as benoxacor, benthiocarb, brassinolide, cloquintocet(mexyl), cyometrinil, daimuron, dichlormid, dicyclonon, dimepiperate, disulfoton, fenchlorazole-ethyl, fenclorim, flurazole, fluxofenim, furilazole, isoxadifen-ethyl, mefenpyr-diethyl, MG 191, MON 4660, naphthalic anhydride (NA), oxabetrinil, R29148 and N-phenyl-sulfonylbenzoic acid amides, to enhance their selectivity. They can additionally be employed to control undesirable vegetation in many crops that have been made tolerant to or resistant to them or to other herbicides by genetic manipulation or by mutation and selection. For example, corn, wheat, rice, soybean, sugarbeet, cotton, canola, and other crops that have been made tolerant or resistant to compounds that are acetolactate synthase inhibitors in sensitive plants can be treated. Many glyphosate and glufosinate tolerant crops can be treated as well, alone or in combination with these herbicides. Some crops (e.g. cotton) have been made tolerant to auxinic herbicides such as 2,4-dichlorophenoxyacetic acid. These herbicides may be used to treat such resistant crops or other auxin tolerant crops.

While it is possible to utilize the 2-(substituted phenyl)-6-hydroxy or alkoxy-5-substituted-4-pyrimidinecarboxylate compounds of Formula I directly as herbicides, it is preferable to use them in mixtures containing an herbicidally effective amount of the compound along with at least one agriculturally acceptable adjuvant or carrier. Suitable adjuvants or carriers should not be phytotoxic to valuable crops, particularly at the concentrations employed in applying the compositions for selective weed control in the presence of crops, and should not react chemically with the compounds of Formula I or other composition ingredients. Such mixtures can be designed for application directly to weeds or their locus or can be concentrates or formulations that are normally diluted with additional carriers and adjuvants before application. They can be solids, such as, for example, dusts, granules, water dispersible granules, or wettable powders, or liquids, such as, for example, emulsifiable concentrates, solutions, emulsions or suspensions.

Suitable agricultural adjuvants and carriers that are useful in preparing the herbicidal mixtures of the invention are well known to those skilled in the art.

Liquid carriers that can be employed include water, toluene, xylene, petroleum naphtha, crop oil, acetone, methyl ethyl ketone, cyclohexanone, trichloroethylene, perchloroethylene, ethyl acetate, amyl acetate, butyl acetate, propylene glycol monomethyl ether and diethylene glycol monomethyl ether, methanol, ethanol, isopropanol, amyl alcohol, ethylene glycol, propylene glycol, glycerine, N-methyl-2-pyrrolidinone, N,N-dimethyl alkylamides, liquid fertilizers and the like. Water is generally the carrier of choice for the dilution of concentrates.

Suitable solid carriers include talc, pyrophyllite clay, silica, attapulgus clay, kaolin clay, kieselguhr, chalk, diatomaceous earth, lime, calcium carbonate, bentonite clay, Fuller's earth, cotton seed hulls, wheat flour, soybean flour, pumice, wood flour, walnut shell flour, lignin, and the like.

It is usually desirable to incorporate one or more surface-active agents into the compositions of the present invention. Such surface-active agents are advantageously employed in both solid and liquid compositions, especially those designed to be diluted with carrier before application. The surface-active agents can be anionic, cationic or nonionic in character and can be employed as emulsifying agents, wetting agents, suspending agents, or for other purposes. Typical surface-active agents include salts of alkyl sulfates, such as diethanol-ammonium lauryl sulfate; alkylarylsulfonate salts, such as calcium dodecyl-benzenesulfonate; alkylphenol-alkylene oxide addition products, such as nonylphenol-C₁₈ ethoxylate; alcohol-alkylene oxide addition products, such as tridecyl alcohol-C₁₆ ethoxylate; soaps, such as sodium stearate; alkylnaphthalene-sulfonate salts, such as sodium dibutylnaphthalenesulfonate; dialkyl esters of sulfosuccinate salts, such as sodium di(2-ethylhexyl)sulfosuccinate; sorbitol esters, such as sorbitol oleate; quaternary amines, such as lauryl trimethyl-ammonium chloride; polyethylene glycol esters of fatty acids, such as poly-ethylene glycol stearate; block copolymers of ethylene oxide and propylene oxide; and salts of mono and dialkyl phosphate esters.

Other adjuvants commonly used in agricultural compositions include compatibilizing agents, antifoam agents, sequestering agents, neutralizing agents and buffers, corrosion inhibitors, dyes, odorants, spreading agents, penetration aids, sticking agents, dispersing agents, thickening agents, freezing point depressants, antimicrobial agents, and the like. The compositions may also contain other compatible components, for example, other herbicides, plant growth regulants, fungicides, insecticides, and the like and can be formulated with liquid fertilizers or solid, particulate fertilizer carriers such as ammonium nitrate, urea and the like.

The concentration of the active ingredients in the herbicidal compositions of this invention is generally from about 0.001 to about 98 percent by weight. Concentrations from about 0.01 to about 90 percent by weight are often employed. In compositions designed to be employed as concentrates, the active ingredient is generally present in a concentration from about 5 to about 98 weight percent, preferably about 10 to about 90 weight percent. Such compositions are typically diluted with an inert carrier, such as water, before application. The diluted compositions usually applied to weeds or the locus of weeds generally contain about 0.0001 to about 1 weight percent active ingredient and preferably contain about 0.001 to about 0.05 weight percent.

The present compositions can be applied to weeds or their locus by the use of conventional ground or aerial dusters, sprayers, and granule applicators, by addition to irrigation water, and by other conventional means known to those skilled in the art.

The following Examples are presented to illustrate the various aspects of this invention and should not be construed as limitations to the claims.

EXAMPLES 1. Preparation of 6-hydroxy-2-(4-chloro-2-fluoro-3-methoxyphenyl)-5-chloropyrimidine-4-carboxylic acid methyl ester (Compound 1)

6-Amino-2-(4-chloro-2-fluoro-3-methoxyphenyl)-5-chloropyrimidine-4-carboxylic acid methyl ester (320 mg, 0.92 mmol, see U.S. Pat. No. 7,300,907 B2 for preparation) was dissolved in 10 mL 1M H₂SO₄ plus 4 mL acetonitrile, warmed to 75° C. and treated in portions with sodium nitrite (690 mg, 10 mmol) over 30 minutes. After stirring for 10 minutes more the mixture was cooled and the solid product was collected by filtration, washed well with water, and dried under vacuum at 80° C. to give 170 mg (53% yield) of 6-hydroxy-2-(4-chloro-2-fluoro-3-methoxyphenyl)-5-chloropyrimidine-4-carboxylic acid methyl ester MP 215-217° C.; MS m/z 346; ¹H NMR (DMSO-d₆): δ 7.47 (m, 2H), 3.94 (s, 3H), 3.91 (s, 3H), 3.34 (br s, 1H).

2. Preparation of 6-hydroxy-2-(4-chloro-2-fluoro-3-methoxyphenyl)-pyrimidine-4-carboxylic acid methyl ester

6-Amino-2-(4-chloro-2-fluoro-3-methoxyphenyl)pyrimidine-4-carboxylic acid methyl ester (300 mg, 0.97 mmol, see U.S. Pat. No. 7,300,907 B2 for preparation) was slurried in 10 mL 1M H₂SO₄ plus 3 mL acetonitrile, heated to 75° C. and treated in portions with sodium nitrite (350 mg, 5 mmol) over a period of 10 minutes. After 40 minutes the mixture was cooled and the yellow precipitate was taken up in 40 mL ethyl acetate, washed with 10 mL water, washed with 10 mL brine, dried, and evaporated to give 170 mg (60% yield) 6-hydroxy-2-(4-chloro-2-fluoro-3-methoxyphenyl)pyrimidine-4-carboxylic acid methyl ester; MS m/z 312, ¹H NMR (DMSO-d₆): δ 7.49 (m, 3H), 3.95 (s, 3H), 3.86 (s, 3H)

3. Preparation of 6-hydroxy-2-(4-chloro-2-fluoro-3-methoxyphenyl)-5-bromopyrimidine-4-carboxylic acid methyl ester (Compound 2)

6-Hydroxy-2-(4-chloro-2-fluoro-3-methoxyphenyl)pyrimidine-4-carboxylic acid methyl ester(150 mg, 0.48 mmol) was combined with N-bromosuccinimide (180 mg, 1.0 mmol) in 7 mL dichloromethane plus 2 mL acetonitrile and heated to reflux for 2 hours. After cooling the volatiles were removed under vacuum and the residue was taken up in 15 mL dichloromethane plus 5 mL water. The organic phase was separated and washed with 10 mL 5% sodium bisulfite solution, washed with 10 mL brine, dried and evaporated to give 120 mg (63% yield) of 6-hydroxy-2-(4-chloro-2-fluoro-3-methoxyphenyl)-5-bromopyrimidine-4-carboxylic acid methyl ester: mp 192-195° C.; MS m/z 390/392; ¹H NMR (DMSO-d₆): δ 7.47 (m, 3H), 3.95 (d, 3H), 3.91 (s, 3H)

4. Preparation of 6-hydroxy-2-(4-chloro-2-fluoro-3-methoxyphenyl)-5-methoxypyrimidine-4-carboxylic acid methyl ester (Compound 3)

6-Amino-2-(4-chloro-2-fluoro-3-methoxyphenyl)-5-methoxypyrimidine-4-carboxylic acid methyl ester (200 mg, 0.61 mmol) was dissolved in 20 mL of 9 molar H₂SO₄ plus 5 mL acetonitrile and treated in portions with NaNO₂ (150 mg, 2.2 mmol). After the addition was complete, the mixture was stirred for 30 minutes at 25° C., cooled in ice-salt and treated carefully with 50% NaOH to bring the pH to ca 0.8. The precipitate was taken up by extracting with two 15 mL portions of EtOAc and the combined extracts were washed with 10 mL sat. NaCl, dried (Na₂SO₄) and evaporated to give the title product 150 mg (75%). Mp: 177-179° C. MS m/z 342; ¹H NMR (DMSO-d₆): δ 7.81 (m, 1H), 7.31 (m, 1H), 4.05 (s, 3H), 4.01 (s, 3H).

5. Preparation of Herbicidal Compositions

In the following illustrative compositions, parts and percentages are by weight.

Emulsifiable Concentrates Formulation A

WT % Compound 1 26.2 Polyglycol 26-3 5.2 Nonionic emulsifier-(di-sec-butyl)- phenyl-poly(oxypropylene)block polymer with (oxyethylene). The polyoxyethelene content is about 12 moles. Witconate P12-20 (Anionic emulsifier- 5.2 calcium dodecylbenzene sulfonate- 60 wt. % active) Aromatic 100 (Xylene range aromatic 63.4 solvent)

Formulation B

WT % Compound 1 3.5 Sunspray 11N (paraffin oil) 40.0 Polyglycol 26-3 19.0 Oleic acid 1.0 Xylene range aromatic solvent 36.5

Formulation C

WT % Compound 2 13.2 Stepon C-65 25.7 Ethomeen T/25 7.7 Ethomeen T/15 18.0 Xylene range aromatic solvent 35.4

Formulation D

WT % Compound 1 30.0 Agrimer A1-10LC (emulsifier) 3.0 N-methyl-2-pyrrolidone 67.0

Formulation E

WT % Compound 2 10.0 Agrimul 70-A (dispersant) 2.0 Amsul DMAP 60 (thickener) 2.0 Emulsogen M (emulsifier) 8.0 Attagel 50 (suspension aid) 2.0 Crop oil 76.0

These concentrates can be diluted with water to give emulsions of suitable concentrations for controlling weeds.

Wettable Powders Formulation F

WT % Compound 1 26.0 Polyglycol 26-3 2.0 Polyfon H 4.0 Zeosyl 100 (Precipitated hydrated SiO₂) 17.0 Barden clay + inerts 51.0

Formulation G

WT % Compound 1 62.4 Polyfon H (sodium salt of lignin 6.0 sulfonate) Sellogen HR (sodium naphthalene 4.0 sulfonate) Zeosyl 100 27.6

Formulation H

WT % Compound 1 1.4 Kunigel V1 (carrier) 30.0 Stepanol ME Dry (wetter) 2.0 Tosnanon GR 31A (binder) 2.0 Kaolin NK-300 Clay (filler) 64.6

The active ingredient is applied to the corresponding carriers and then these are mixed and ground to yield wettable powders of excellent wettability and suspension power. By diluting these wettable powders with water it is possible to obtain suspensions of suitable concentrations for controlling weeds.

Water Dispersible Granules Formulation I

WT % Compound 1 26.0 Sellogen HR 4.0 Polyfon H 5.0 Zeosyl 100 17.0 Kaolinite clay 48.0

The active ingredient is added to the hydrated silica, which is then mixed with the other ingredients and ground to a powder. The powder is agglomerated with water and sieved to provide granules in the range of −10 to +60 mesh. By dispersing these granules in water it is possible to obtain suspensions of suitable concentrations for controlling weeds.

Granules Formulation J

WT % Compound 1 5.0 Celetom MP-88 95.0

The active ingredient is applied in a polar solvent such as N-methylpyrollidinone, cyclohexanone, gamma-butyrolactone, etc. to the Celetom MP 88 carrier or to other suitable carriers. The resulting granules can be applied by hand, granule applicator, airplane, etc. in order to control weeds.

Formulation K

WT % Compound 1 1.0 Polyfon H 8.0 Nekal BA 77 2.0 Zinc Stearate 2.0 Barden Clay 87.0

All materials are blended and ground to a powder then water is added and the clay mixture is stirred until a paste is formed. The mixture is extruded through a die to provide granules of proper size.

6. Evaluation of General Postemergence Herbicidal Activity

Seeds or nutlets of the desired test plant species were planted in Sun Gro MetroMix® 306 planting mixture, which typically has a pH of 6.0 to 6.8 and an organic matter content of about 30 percent, in plastic pots with a surface area of 64 square centimeters. When required to ensure good germination and healthy plants, a fungicide treatment and/or other chemical or physical treatment was applied. The plants were grown for 7-21 days in a greenhouse with an approximate 15 hour photoperiod which was maintained at about 23-29° C. during the day and 22-28° C. during the night. Nutrients and water were added on a regular basis and supplemental lighting was provided with overhead metal halide 1000-Watt lamps as necessary. The plants were employed for testing when they reached the first or second true leaf stage.

A weighed amount, determined by the highest rate to be tested, of each test compound was dissolved in 4 mL of a 97:3 v/v (volume/volume) mixture of acetone and dimethyl sulfoxide (DMSO) to obtain concentrated stock solutions. If the test compound did not dissolve readily, the mixture was warmed and/or sonicated. The concentrated stock solutions obtained were diluted with 20 mL of an aqueous mixture containing acetone, water, isopropyl alcohol, DMSO, Atplus 411F crop oil concentrate, and Triton® X-155 surfactant in a 48.5:39:10:1.5:1.0:0.02 v/v ratio to obtain spray solutions containing the highest application rates. Additional application rates were obtained by serial dilution of 12 mL of the high rate solution into a solution containing 2 mL of 97:3 v/v (volume/volume) mixture of acetone and dimethyl sulfoxide (DMSO) and 10 mL of an aqueous mixture containing acetone, water, isopropyl alcohol, DMSO, Atplus 411F crop oil concentrate, and Triton X-155 surfactant in a 48.5:39:10:1.5:1.0:0.02 v/v ratio to obtain 1/2X, 1/4X, 1/8X and 1/16X rates of the high rate. Compound requirements are based upon a 12 mL application volume at a rate of 187 L/ha. Formulated compounds were applied to the plant material with an overhead Mandel track sprayer equipped with a 8002E nozzles calibrated to deliver 187 L/ha over an application area of 0.503 square meters at a spray height of 18 inches (43 cm) above the average plant canopy height. Control plants were sprayed in the same manner with the solvent blank.

The treated plants and control plants were placed in a greenhouse as described above and watered by sub-irrigation to prevent wash-off of the test compounds. After 14 days, the condition of the test plants as compared with that of the untreated plants was determined visually and scored on a scale of 0 to 100 percent where 0 corresponds to no injury and 100 corresponds to complete kill.

Some of the compounds tested, application rates employed, plant species tested, and results are given in Table 1.

TABLE 1 Post-emergent Weed Control Rate % Growth Reduction Compound g ai/ha CHEAL AMARE EPHHL HELAN 1 280 100  100 100 90 2 280 95 100 100 85 3 280 90  40 100 10 CHEAL - Lambsquarters (Chenopodium album) AMARE - Redroot Pigweed (Amatanthus retroflexus) EPHHL - Wild Pointsettia (Euphorbia heterophylla) HELAN - Common Sunflower (Helianthus annuus) 

1. A compound of the formula I

wherein Q represents a halogen, cyano, C₁-C₄ alkyl, C₁-C₄ haloalkyl, C₂-C₄ alkenyl and epoxides thereof, C₂-C₄ haloalkenyl and epoxides thereof, C₂-C₄ alkynyl or C₂-C₄ haloalkynyl; R₁ represents H or C₁-C₄ alkyl; W represents H or halogen; X represents halogen; Y represents halogen, C₁-C₄ alkyl, C₁-C₄ alkoxy, C₁-C₄ alkylthio, C₁-C₄ haloalkyl, C₁-C₄ haloalkoxy, C₁-C₄ haloalkylthio, —NR₂R₃, C₁-C₄ alkoxy-substituted C₁-C₄ alkyl, C₁-C₄ haloalkoxy-substituted C₁-C₄ alkyl, C₂-C₄ alkenyl, C₂-C₄ haloalkenyl or C₁-C₄ haloalkyl-substituted carbonyl; Z represents halogen, C₁-C₄ alkyl or C₁-C₄ haloalkyl; and R₂ and R₃ independently represent H or C₁-C₄ alkyl; and agriculturally acceptable derivatives of the carboxylic acid group.
 2. A compound of claim 1 in which the agriculturally acceptable derivatives of the carboxylic acid group are agriculturally acceptable salts, esters and amides.
 3. A compound of claim 1 in which Q represents Cl, Br C₂-C₄ alkenyl; R₁ represents H; W represents H; X represents F; Y represents F or OCH₃; and Z represents Cl.
 4. A herbicidal composition comprising a herbicidally effective amount of a compound according to claim 1, in a mixture with an agriculturally acceptable adjuvant or carrier.
 5. A method of controlling undesirable vegetation which comprises contacting the vegetation or the locus thereof with or applying to the soil to prevent the emergence of vegetation a herbicidal composition according to claim
 4. 